1. Field of the Invention
The present invention relates to a camera rotation device and, more particularly, to miniaturization of a camera rotation device.
2. Description of the Related Art
A monitoring or surveillance camera rotation device is previously known as an example of a camera rotation device. A common surveillance camera rotation device has a chassis which can be mounted on ceilings or the like, and a mechanism for supporting a camera so that the camera can rotate in pan and tilt directions with respect to the chassis. In addition, a motor for rotating the camera is mounted on the chassis.
As mentioned above, conventional devices have a motor provided separately from the camera rotation mechanism on the chassis. Generally speaking, with conventional devices, a space is reserved beneath a stage floor on which a camera is to be mounted and rotated, with a motor then being located in this space. Such conventional devices are therefore larger and relatively more expensive because space is required to mount the motor so as to be separate from the camera rotation mechanism. Thus, it is desired to realize a smaller-sized and less expensive rotation device.
To solve the above problems, it is an object of the present invention to provide a small-sized camera rotation device.
One aspect of the present invention is a camera rotation device comprising a motor provided on a rotated side (swiveled side) rotating with a camera with respect to a rotating side (swiveling side) which rotates the camera; and a torque (rotating force) transfer means for transferring torque (rotating force) of the motor to the rotating side and thus rotating the motor as well as the camera on the rotated side by reaction force of the rotating side. In comparison with that of the conventional devices which have the motor on the chassis separate from the rotation mechanism, this structure reduces space for mounting the motor and allows a smaller rotation device.
When the rotation device has two or more rotation mechanisms for two or more rotation directions (typically a pan direction and a tilt direction), the present invention can be applied to one or more of the mechanisms
Another aspect of the present invention is a camera rotation device comprising a base section; a pan section operable to rotate in a pan direction with respect to the base section; a pan motor provided in the pan section; a pan torque transfer means for transferring torque of the pan motor to the base section and rotating the pan section by reaction force of the base section; a tilt section operable to rotate in a tilt direction with respect to the pan section; a tilt motor provided in the tilt section; and a tilt torque transfer means which transfers torque of the tilt motor to the pan section and rotates the tilt section by reaction force of the pan section. The pan motor and the tilt motor are respectively mounted in the pan section and the tilt section. Thus, in comparison with the conventional devices which have a motor on a base, the rotation device according to the present invention needs less space for mounting the motors and can be smaller in size.
The camera rotation device according to the present invention may further comprise a pan torque transfer means and a tilt torque transfer means composed of spur gears. Spur gears are reversible. That is, spur gears on the rotating side and the rotated side spin each other even when a person rotates the camera by hand. The above structure therefore makes it possible to avoid putting a strain on the torque transfer means even if someone carelessly, as a prank or the like, rotates the camera by hand. Accordingly, failure of the rotation device will be avoided.
Furthermore, in the camera rotation device according to the present invention, the pan torque transfer means may comprise a pan end gear fixed to the base section and at least one pan intermediate reduction gear interposed between the pan motor and the pan end gear, and the tilt torque transfer means may comprise a tilt end gear fixed to the pan section and at least one tilt intermediate reduction gear interposed between the tilt motor and the tilt end gear. This structure, having a reduction gear mechanism, optimizes the swiveling speed.
The pan intermediate reduction gear is, like the pan motor, provided preferably in the pan section. This saves space and further miniaturizes the device compared to the case of the pan intermediate reduction gear being provided on the base. It is also preferable to provide the tilt intermediate reduction gear in the bit section, as the gear only requires a small amount of space and the device can be smaller.
Moreover, a camera rotation device according to the present invention may have a structure in which at least one of the pan intermediate reduction gears and at least one of the tilt intermediate reduction gears are used in common with each other. This structure reduces costs by providing commonality of parts. Commonality of parts also lightens the workers"" workload of discriminating among parts during assembly, and therefore facilitates assembly tasks and increases productivity.
Still another aspect of the present invention is a camera rotation device comprising a base section; a first rotation section provided rotatably in a first direction with respect to the base section; a first rotation drive means which rotates the first rotation section with respect to the base section; a second rotation section provided rotatably in a second direction with respect to the first rotation section; and a second rotation drive means which rotates the second rotation section with respect to the first rotation section. In this device, at least one of the first rotation drive means and the second rotation drive means comprises a motor provided on a rotated side; and a torque transfer means which transfers torque of the motor on the rotated side to a rotating side and therefore rotates the motor as well as the rotated side by reaction force of the rotating side. Rotation directions of this structure are not limited to a pan direction and a tilt direction. Furthermore, the structure of the present invention, which has a motor mounted on the rotated side, can be applied to one of the two rotation mechanisms for each direction as well as to both directions as a matter of course. This structure, as is the case with the structure mentioned in the preceding paragraphs, allows a smaller camera rotation device.
In the camera rotation device according to the present invention, the torque transfer means may be composed of spur gears. As described above, this structure allows the torque transfer means to be reversible, and therefore makes it possible to avoid a strain put on the torque transfer means. Thus, failure of the rotation device will be avoided.
In the camera rotation device according to the present invention, the torque transfer means may comprise a stationary gear fixed to the rotating side and at least one intermediate reduction gear interposed between the motor and the stationary gear. This structure makes the device smaller because of the reason mentioned above.
In the camera rotation device according to the present invention, both the first rotation drive means and the second rotation drive means may comprise the motor and the torque transfer means, and at least one each of the intermediate reduction gears provided on the two torque transfer means of the first rotation drive means and the second rotation drive means may be in common with each other. This structure reduces costs for the reasons mentioned above. Moreover, the structure facilitates assembly tasks and therefore increases productivity.